The Lakers cancelling their season becaues of Kobe's death is less comparable to Shuri taking over the mantle than it is the "or don't even bother" notion. Just as the season will go on for the Laker, so will the BP movie. It's simply a matter of replacing Kobe postion, the same way they will replace Bosemans... the question being whether they will replace it with Shuri or a new T'Challa or even Killmonger or Kasper Cole. Again, there are options.
As far as whether or not it's up for debate... clearly it is, because here we are. People have been debating about it for quite some time. Even more mainstream media has discussed the matter. So I don't agree the issue is quite as clear cut as you believe it to be. I think there are a lot of people who want different thngs, and I think there are valid reasons for why they think it. Though certainly you may end up being 100% about Coogler wanting to continue telling T'Challa's story... and if that's the case, they'll recast and that will be that. Coogler will do what Coogler wants to do, and the people who don't get their way will simply have to live with it.